HS2 contracts which should have cost £19.5 billion in total have already risen in price by another £6.5 billion, according to HS2 CEO Mark Wild.

Mr Wild was giving evidence to the Commons Transport Committee. He said that there had been ‘optimism bias’ when projects were being costed, and that control of the scheme had been lost

He has been brought in to undertake a complete ‘reset’ of the scheme, which should have welcomed its first passengers next year but has now been put back to an unknown opening date after 2033.

Only 60 per cent of the civil engineering on the 160km/h route has been completed, although it should have been virtually finished by now.

He told the Committee: ‘The bottom line is that, at the notice to proceed, the contractors could not price the risk. What we’re seeing is the crystallisation of risk: they should have cost £19.5 billion and we’ve already spent £26 billion and we’re just over halfway done.

‘If you lose control of the programme, you end up at the extreme end of optimism bias, which ends up in delusion. The problem with HS2 is we lost control of the programme.’

He predicted an eventual ‘overspend’ of between 50 and 100 per cent.

Rail minister Lord Hendy, meanwhile, questioned the need for trains travelling at 350km/h.

He said: ‘It is hard to understand why there was such zealotry about the highest-speed railway in a relatively small country.’

The maximum speed on HS1 is 300km/h, and high speed lines on the continent rarely offer more than 320km/h, even though they cover much greater distances than the remaining section of HS2.

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